1. Field of the Invention
The present invention relates to a heat dissipation device, and more particularly to a heat dissipation device having a plurality of thermoelectric coolers to improve heat dissipation efficiency thereof, by lowering a temperature of an airflow before it is driven by a fan to flow to a fin group.
2. Description of Related Art
When a CPU of an electronic apparatus, for example, a computer operates, heat must be quickly carried away from the CPU so that the operation of the CPU can be maintained in a normal condition. A conventional heat dissipation apparatus for this purpose commonly comprises of a heat sink having a plurality of upright fins, a base adapted for being mounted on the top of the CPU, and a fan mounted on the heat sink above the CPU. The heat sink is designed to increase length of the fins to improve heat dissipation efficiency thereof. However, increasing the length of the fins also increases a thickness of a border layer of air on a top surface of the fins. The border layer of air is a layer of stagnant air formed on a surface of an article. The thickness of the border layer of air is inversely proportional to the amount of heat that can be transferred from the surface of the heat sink to the surrounding air. Furthermore, the length of the fins can not increase too long due to space limitations in modern computers. Therefore, to improve the heat dissipating capacity of the heat sink by increasing the length of the fins of the heat sink has its limitation.
Another factor that can determine the heat dissipating capacity of a heat sink is the temperature difference between the heat sink and an airflow passing through the heat sink. The temperature difference is proportional to the amount of heat that can be transferred from the heat sink. Generally, the average temperature of ambient air surrounding the heat sink is not much lower than that of the heat sink, and the temperature difference between the airflow and the heat sink is small. The amount of heat that is transferred from the heat sink to the airflow is limited.
What is needed, therefore, is a heat dissipation device which has a high heat dissipating capacity.